Low naphthenic liquid crystalline polymer composition for use in molded parts with a small dimensional tolerance

ABSTRACT

A thermoplastic composition that comprises a low-naphthenic, thermotropic liquid crystalline polymer blended with a combination of flow modifiers is provided. More particularly, one of the flow modifiers is a hydroxy-functional compound that contains or more hydroxyl functional groups. Without intending to be limited by theory, it is believed that the hydroxyl functional groups can react with the polymer chain to shorten its length and thus reduce melt viscosity. Aromatic dicarboxylic acids are also employed as a flow modifier in the thermoplastic composition. Again, without intending to be limited by theory, it is believed that such acids can combine smaller chains of the polymer together after they have been cut by hydroxy-functional compounds. This helps maintain the mechanical properties of the composition even after its melt viscosity has been reduced.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationSer. Nos. 61/559,822, filed on Nov. 15, 2011, and 61/678,267, filed onAug. 1, 2012, which are incorporated herein in their entirety byreference thereto.

BACKGROUND OF THE INVENTION

Electrical components often contain molded parts that are formed from aliquid crystalline, thermoplastic resin. Recent demands on theelectronic industry have dictated a decreased size of such components toachieve the desired performance and space savings. Unfortunately,however, it is often difficult to adequately fill a mold cavity of asmall dimension with most conventional liquid crystalline polymers. Forinstance, conventional formulations are generally derived from aromatichydroxy acid monomers (e.g., hydroxybenzoic acid (“HBA”) or6-hydroxy-2-naphthoic acid (“HNA”)), either alone or in conjunction withother aromatic monomers, such as diacids (e.g., terephthalic acid (“TA”)or isophthalic acid (“IA”)) and/or diols (e.g., hydroquinone (“HQ”),acetaminophen (“APAP”), and 4,4′-biphenol (“BP”)). Unfortunately, suchpolymers tend to display a very high solid-to-liquid transitiontemperature (“melting temperature”), which precludes their ability toflow well at temperatures below the decomposition temperature.

To suppress the melting point and generate materials that can flow,additional monomers are often incorporated into the polymer backbone asa repeating unit. One commonly employed melting point suppressant isnaphthalene-2,6-dicarboxylic acid (“NDA”), which is generally believedto disrupt the linear nature of the polymer backbone and thereby reducethe melting temperature. The melting point of a wholly aromatic liquidcrystal polyester may be lowered by substituting NDA for a portion ofthe terephthalic acid in a polyester of terephthalic acid, hydroquinoneand p-hydroxybenzoic acid. In addition to NDA, other naphthenic acidshave also been employed as a melt point suppressant. For instance,6-hydroxy-2-naphthoic acid (“HNA”) has been employed as a melting pointsuppressant for a polyester formed from an aromatic diol and an aromaticdicarboxylic acid. Despite the benefits achieved, the aforementionedpolymers still have various drawbacks. For example, the reactivity ofthe naphthenic acids with other monomeric constituents can haveunintended consequences on the final mechanical and thermal propertiesof the polymer composition. This is particularly problematic for moldedparts having a small dimensional tolerance. In addition to functionalconcerns, the high cost of naphthenic acids also dictates that the needfor others solutions to the problems noted.

As such, a need exists for a low naphthenic, liquid crystallinethermoplastic composition that can readily fill mold cavities of a smalldimension, and yet still attain good mechanical properties.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, athermoplastic composition is disclosed that comprises at least onethermotropic liquid crystalline polymer. The total amount of repeatingunits in the polymer derived from naphthenic hydroxcarboxylic ornaphthenic dicarboxylic acids is no more than 15 mol. %. Thethermoplastic composition further comprises at least onehydroxy-functional compound and at least one aromatic dicarboxylic acid,wherein the weight ratio of hydroxy-functional compounds to aromaticdicarboxylic acids in the composition is from about 0.1 to about 30.Further, the thermoplastic composition has a melt viscosity of fromabout 0.5 to about 100 Pa-s, as determined in accordance with ISO TestNo. 11443 at a shear rate of 1000 seconds⁻¹ and temperature that is 15°C. above the melting temperature of the composition.

In accordance with another embodiment of the present invention, a moldedpart is disclosed that has at least one dimension of about 500micrometers or less. The part contains a thermoplastic composition thatcomprises at least one thermotropic liquid crystalline polymer. Thetotal amount of repeating units in the polymer derived from naphthenichydroxcarboxylic or naphthenic dicarboxylic acids is no more than 15mol. %. The thermoplastic composition further comprises at least onehydroxy-functional compound and at least one aromatic dicarboxylic acid,wherein the weight ratio of hydroxy-functional compounds to aromaticdicarboxylic acids in the composition is from about 0.1 to about 30.

Other features and aspects of the present invention are set forth ingreater detail below.

BRIEF DESCRIPTION OF THE FIGURES

A full and enabling disclosure of the present invention, including thebest mode thereof to one skilled in the art, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures, in which:

FIG. 1 is an exploded perspective view of one embodiment of a fine pitchelectrical connector that may be formed according to the presentinvention;

FIG. 2 is a front view of opposing walls of the fine pitch electricalconnector of FIG. 1;

FIG. 3 is a schematic illustration of one embodiment of an extruderscrew that may be used to form the thermoplastic composition of thepresent invention;

FIGS. 4-5 are respective front and rear perspective views of anelectronic component that can employ an antenna structure formed inaccordance with one embodiment of the present invention; and

FIGS. 6-7 are perspective and front views of a compact camera module(“CCM”) that may be formed in accordance with one embodiment of thepresent invention.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentinvention.

Generally speaking, the present invention is directed to a thermoplasticcomposition that comprises a low-naphthenic, thermotropic liquidcrystalline polymer blended with a combination of flow modifiers thathelp achieve a low melt viscosity without sacrificing the mechanicalproperties of the composition. More particularly, one of the flowmodifiers is a hydroxy-functional compound that contains or morehydroxyl functional groups. Without intending to be limited by theory,it is believed that the hydroxyl functional groups can react with thepolymer chain to shorten its length and thus reduce melt viscosity.Aromatic dicarboxylic acids are also employed as a flow modifier in thethermoplastic composition. Again, without intending to be limited bytheory, it is believed that such acids can combine smaller chains of thepolymer together after they have been cut by hydroxy-functionalcompounds. This helps maintain the mechanical properties of thecomposition even after its melt viscosity has been reduced. To helpachieve the properties desired, the weight ratio of thehydroxy-functional compounds to the aromatic dicarboxylic acids in thecomposition is typically 0.1 to about 30, in some embodiments from about0.5 to about 30, in some embodiments from about 1 to about 30, in someembodiments from about 2 to about 25, and in some embodiments, fromabout 5 to about 20.

As a result of the present invention, the melt viscosity of thethermoplastic composition is generally low enough so that it can readilyflow into the cavity of a mold having small dimensions. For example, inone particular embodiment, the thermoplastic composition may have a meltviscosity of from about 0.5 to about 100 Pa-s, in some embodiments fromabout 1 to about 80 Pa-s, and in some embodiments, from about 5 to about50 Pa-s. Melt viscosity may be determined in accordance with ISO TestNo. 11443 at a shear rate of 1000 sec⁻¹ and temperature that is 15° C.above the melting temperature of the composition (e.g., 350° C.).

Conventionally, it was believed that thermoplastic compositions havingsuch the low viscosity noted above would not also possess sufficientlygood thermal and mechanical properties to enable their use in certaintypes of applications. Contrary to conventional thought, however, thethermoplastic composition of the present invention has been found topossess both excellent thermal and mechanical properties. For example,the composition may possess a high impact strength, which is useful whenforming small parts. The composition may, for instance, possess a Charpynotched impact strength greater than about 4 kJ/m², in some embodimentsfrom about 5 to about 40 kJ/m², and in some embodiments, from about 6 toabout 30 kJ/m², measured at 23° C. according to ISO Test No. 179-1)(technically equivalent to ASTM D256, Method B). The tensile andflexural mechanical properties of the composition are also good. Forexample, the thermoplastic composition may exhibit a tensile strength offrom about 20 to about 500 MPa, in some embodiments from about 50 toabout 400 MPa, and in some embodiments, from about 100 to about 350 MPa;a tensile break strain of about 0.5% or more, in some embodiments fromabout 0.6% to about 10%, and in some embodiments, from about 0.8% toabout 3.5%; and/or a tensile modulus of from about 5,000 MPa to about20,000 MPa, in some embodiments from about 8,000 MPa to about 20,000MPa, and in some embodiments, from about 10,000 MPa to about 15,000 MPa.The tensile properties may be determined in accordance with ISO Test No.527 (technically equivalent to ASTM D638) at 23° C. The thermoplasticcomposition may also exhibit a flexural strength of from about 20 toabout 500 MPa, in some embodiments from about 50 to about 400 MPa, andin some embodiments, from about 100 to about 350 MPa; a flexural breakstrain of about 0.5% or more, in some embodiments from about 0.6% toabout 10%, and in some embodiments, from about 0.8% to about 3.5%;and/or a flexural modulus of from about 5,000 MPa to about 20,000 MPa,in some embodiments from about 8,000 MPa to about 20,000 MPa, and insome embodiments, from about 10,000 MPa to about 15,000 MPa. Theflexural properties may be determined in accordance with ISO Test No,178 (technically equivalent to ASTM D790) at 23° C.

The melting temperature of the composition may likewise be from about250° C. to about 400° C., in some embodiments from about 270° C. toabout 380° C., and in some embodiments, from about 300° C. to about 360°C. The melting temperature may be determined as is well known in the artusing differential scanning calorimetry (“DSC”), such as determined byISO Test No. 11357. Even at such melting temperatures, the ratio of thedeflection temperature under load (“DTUL”), a measure of short term heatresistance, to the melting temperature may still remain relatively high.For example, the ratio may range from about 0.65 to about 1.00, in someembodiments from about 0.66 to about 0.95, and in some embodiments, fromabout 0.67 to about 0.85. The specific DTUL values may, for instance,range from about 200° C. to about 300° C., in some embodiments fromabout 210° C. to about 280° C., and in some embodiments, from about 215°C. to about 260° C. Such high DTUL values can, among other things, allowthe use of high speed processes often employed during the manufacture ofcomponents having a small dimensional tolerance.

The thermotropic liquid crystalline polymer generally has a high degreeof crystallinity that enables it to effectively fill the small spaces ofa mold. The amount of such liquid crystalline polymers is typically fromabout 20 wt % to about 90 wt. %, in some embodiments from about 30 wt. %to about 80 wt. %, and in some embodiments, from about 40 wt. % to about75 wt. % of the thermoplastic composition. Suitable thermotropic liquidcrystalline polymers may include aromatic polyesters, aromaticpoly(esteramides), aromatic poly(estercarbonates), aromatic polyamides,etc., and may likewise contain repeating units formed from one or morearomatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromaticdiols, aromatic aminocarboxylic acids, aromatic amines, aromaticdiamines, etc., as well as combinations thereof.

Aromatic polyesters, for instance, may be obtained by polymerizing (1)two or more aromatic hydroxycarboxylic acids; (2) at least one aromatichydroxycarboxylic acid, at least one aromatic dicarboxylic acid, and atleast one aromatic diol; and/or (3) at least one aromatic dicarboxylicacid and at least one aromatic diol. Examples of suitable aromatichydroxycarboxylic acids include, 4-hydroxybenzoic acid;4-hydroxy-4′-biphenylcarboxylic acid; 2-hydroxy-6-naphthoic acid;2-hydroxy-5-naphthoic acid; 3-hydroxy-2-naphthoic acid;2-hydroxy-3-naphthoic acid; 4′-hydroxyphenyl-4-benzoic acid;3′-hydroxyphenyl-4-benzoic acid; 4′-hydroxyphenyl-3-benzoic acid, etc.,as well as alkyl, alkoxy, aryl and halogen substituents thereof.Examples of suitable aromatic dicarboxylic acids include terephthalicacid; isophthalic acid; 2,6-naphthalenedicarboxylic acid; diphenylether-4,4′-dicarboxylic acid; 1,6-naphthalenedicarboxylic acid;2,7-naphthalenedicarboxylic acid; 4,4′-dicarboxybiphenyl;bis(4-carboxyphenyl)ether; bis(4-carboxyphenyl)butane;bis(4-carboxyphenyl)ethane; bis(3-carboxyphenyl)ether;bis(3-carboxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl andhalogen substituents thereof. Examples of suitable aromatic diolsinclude hydroquinone; resorcinol; 2,6-dihydroxynaphthalene;2,7-dihydroxynaphthalene; 1,6-dihydroxynaphthalene;4,4′-dihydroxybiphenyl; 3,3′-dihydroxybiphenyl; 3,4-dihydroxybiphenyl;4,4′-dihydroxybiphenyl ether; bis(4-hydroxyphenyl)ethane, etc., as wellas alkyl, alkoxy, aryl and halogen substituents thereof. The synthesisand structure of these and other aromatic polyesters may be described inmore detail in U.S. Pat. Nos. 4,161,470; 4,473,682; 4,522,974;4,375,530; 4,318,841; 4,256,624; 4,219,461; 4,083,829; 4,184,996;4,279,803; 4,337,190; 4,355,134; 4,429,105; 4,393,191; 4,421,908;4,434,262; and 5,541,240.

Liquid crystalline polyesteramides may likewise be obtained bypolymerizing (1) at least one aromatic hydroxycarboxylic acid and atleast one aromatic aminocarboxylic acid; (2) at least one aromatichydroxycarboxylic acid, at least one aromatic dicarboxylic acid, and atleast one aromatic amine and/or diamine optionally having phenolichydroxy groups; and (3) at least one aromatic dicarboxylic acid and atleast one aromatic amine and/or diamine optionally having phenolichydroxy groups. Suitable aromatic amines and diamines may include, forinstance, 3-aminophenol; 4-aminophenol; 1,4-phenylenediamine;1,3-phenylenediamine, etc., as well as alkyl, alkoxy, aryl and halogensubstituents thereof. In one particular embodiment, the aromaticpolyesteramide contains monomer units derived from 2,6-hydroxynaphthoicacid, terephthalic acid, and 4-aminophenol. In another embodiment, thearomatic polyesteramide contains monomer units derived from2,6-hydroxynaphthoic acid, and 4-hydroxybenzoic acid, and 4-aminophenol,as well as other optional monomers (e.g., 4,4′-dihydroxybiphenyl and/orterephthalic acid). The synthesis and structure of these and otheraromatic poly(esteramides) may be described in more detail in U.S. Pat.Nos. 4,339,375; 4,355,132; 4,351,917; 4,330,457; 4,351,918; and5,204,443.

As indicated above, the liquid crystalline polymer is a “low naphthenic”polymer to the extent that it contains a minimal content of repeatingunits derived from naphthenic hydroxycarboxylic acids and naphthenicdicarboxylic acids, such as naphthalene-2,6-dicarboxylic acid (“NDA”),6-hydroxy-2-naphthoic acid (“HNA”), or combinations thereof. That is,the total amount of repeating units derived from naphthenichydroxycarboxylic and/or dicarboxylic acids (e.g., NDA, HNA, or acombination of HNA and NDA) is typically no more than 15 mol. %, in someembodiments no more than about 13 mol. %, in some embodiments no morethan about 10 mol. %, in some embodiments no more than about 8 mol. %,and in some embodiments, from 0 mol. % to about 5 mol. % of the polymer(e.g., 0 mol. %). Despite the absence of a high level of conventionalnaphthenic acids, it is believed that the resulting “low naphthenic”polymers are still capable of exhibiting good thermal and mechanicalproperties, as described above.

In one particular embodiment, for example, a “low naphthenic” aromaticpolyester may be formed that contains monomer repeat units derived from4-hydroxybenzoic acid and terephthalic acid. The monomer units derivedfrom 4-hydroxybenzoic acid (“HBA”) may constitute from about 40 mol. %to about 95 mol. %, in some embodiments from about 45 mol. % to about 90mol. %, and in some embodiments, from about 50 mol. % to about 80 mol. %of the polymer, while the monomer units derived from terephthalic acid(“TA”) and/or isophthalic acid (“IA”) may each constitute from about 1mol. % to about 30 mol. %, in some embodiments from about 2 mol. % toabout 25 mol. %, and in some embodiments, from about 3 mol. % to about20 mol. % of the polymer. Other monomeric units may optionally beemployed, such as aromatic diols (e.g., 4,4′-biphenol, hydroquinone,etc.). For example, hydroquinone (“HQ”), 4,4′-biphenol (“BP”), and/oracetaminophen (“APAP”) may each constitute from about 1 mol. % to about30 mol. %, in some embodiments from about 2 mol. % to about 25 mol. %,and in some embodiments, from about 3 mol. % to about 20 mol. % whenemployed. If desired, the polymer may also contain a small amount of6-hydroxy-2-naphthoic acid (“HNA”) within the ranges noted above.

The liquid crystalline polymers may be prepared by introducing theappropriate monomer(s) (e.g., aromatic hydroxycarboxylic acid, aromaticdicarboxylic acid, aromatic diol, aromatic amine, aromatic diamine,etc.) into a reactor vessel to initiate a polycondensation reaction. Theparticular conditions and steps employed in such reactions are wellknown, and may be described in more detail in U.S. Pat. No. 4,161,470 toCalundann; U.S. Pat. No. 5,616,680 to Linstid, III, et al.; U.S. Pat.No. 6,114,492 to Linstid, III. et al.; U.S. Pat. No. 6,514,611 toShepherd, et al.; and WO 2004/058851 to Waggoner, which are incorporatedherein in their entirety by reference thereto for all relevant purposes.The vessel employed for the reaction is not especially limited, althoughit is typically desired to employ one that is commonly used in reactionsof high viscosity fluids. Examples of such a reaction vessel may includea stirring tank-type apparatus that has an agitator with avariably-shaped stirring blade, such as an anchor type, multistage type,spiral-ribbon type, screw shaft type, etc., or a modified shape thereof.Further examples of such a reaction vessel may include a mixingapparatus commonly used in resin kneading, such as a kneader, a rollmill, a Banbury mixer, etc.

If desired, the reaction may proceed through the acetylation of themonomers as referenced above and known the art. This may be accomplishedby adding an acetylating agent (e.g., acetic anhydride) to the monomers.Acetylation is generally initiated at temperatures of about 90° C.During the initial stage of the acetylation, reflux may be employed tomaintain vapor phase temperature below the point at which acetic acidbyproduct and anhydride begin to distill. Temperatures duringacetylation typically range from between 90° C. to 150° C., and in someembodiments, from about 110° C. to about 150° C. If reflux is used, thevapor phase temperature typically exceeds the boiling point of aceticacid, but remains low enough to retain residual acetic anhydride. Forexample, acetic anhydride vaporizes at temperatures of about 140° C.Thus, providing the reactor with a vapor phase reflux at a temperatureof from about 110° C. to about 130° C. is particularly desirable. Toensure substantially complete reaction, an excess amount of aceticanhydride may be employed. The amount of excess anhydride will varydepending upon the particular acetylation conditions employed, includingthe presence or absence of reflux. The use of an excess of from about 1to about 10 mole percent of acetic anhydride, based on the total molesof reactant hydroxyl groups present is not uncommon.

Acetylation may occur in a separate reactor vessel, or it may occur insitu within the polymerization reactor vessel. When separate reactorvessels are employed, one or more of the monomers may be introduced tothe acetylation reactor and subsequently transferred to thepolymerization reactor. Likewise, one or more of the monomers may alsobe directly introduced to the reactor vessel without undergoingpre-acetylation.

In addition to the monomers and optional acetylating agents, othercomponents may also be included within the reaction mixture to helpfacilitate polymerization. For instance, a catalyst may be optionallyemployed, such as metal salt catalysts (e.g., magnesium acetate, tin(I)acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassiumacetate, etc.) and organic compound catalysts (e.g., N-methylimidazole).Such catalysts are typically used in amounts of from about 50 to about500 parts per million based on the total weight of the recurring unitprecursors. When separate reactors are employed, it is typically desiredto apply the catalyst to the acetylation reactor rather than thepolymerization reactor, although this is by no means a requirement.

The reaction mixture is generally heated to an elevated temperaturewithin the polymerization reactor vessel to initiate meltpolycondensation of the reactants. Polycondensation may occur, forinstance, within a temperature range of from about 210° C. to about 400°C., and in some embodiments, from about 250° C. to about 350° C. Forinstance, one suitable technique for forming an aromatic polyester mayinclude charging precursor monomers (e.g., 4-hydroxybenzoic acid and2,6-hydroxynaphthoic acid) and acetic anhydride into the reactor,heating the mixture to a temperature of from about 90° C. to about 150°C. to acetylize a hydroxyl group of the monomers (e.g., formingacetoxy), and then increasing the temperature to a temperature of fromabout 210° C. to about 400° C. to carry out melt polycondensation. Asthe final polymerization temperatures are approached, volatilebyproducts of the reaction (e.g., acetic acid) may also be removed sothat the desired molecular weight may be readily achieved. The reactionmixture is generally subjected to agitation during polymerization toensure good heat and mass transfer, and in turn, good materialhomogeneity. The rotational velocity of the agitator may vary during thecourse of the reaction, but typically ranges from about 10 to about 100revolutions per minute (“rpm”), and in some embodiments, from about 20to about 80 rpm. To build molecular weight in the melt, thepolymerization reaction may also be conducted under vacuum, theapplication of which facilitates the removal of volatiles formed duringthe final stages of polycondensation. The vacuum may be created by theapplication of a suctional pressure, such as within the range of fromabout 5 to about 30 pounds per square inch (“psi”), and in someembodiments, from about 10 to about 20 psi.

Following melt polymerization, the molten polymer may be discharged fromthe reactor, typically through an extrusion orifice fitted with a die ofdesired configuration, cooled, and collected. Commonly, the melt isdischarged through a perforated die to form strands that are taken up ina water bath, pelletized and dried. The resin may also be in the form ofa strand, granule, or powder. While unnecessary, it should also beunderstood that a subsequent solid phase polymerization may be conductedto further increase molecular weight. When carrying out solid-phasepolymerization on a polymer obtained by melt polymerization, it istypically desired to select a method in which the polymer obtained bymelt polymerization is solidified and then pulverized to form a powderyor flake-like polymer, followed by performing solid polymerizationmethod, such as a heat treatment in a temperature range of 200° C. to350° C. under an inert atmosphere (e.g., nitrogen).

Regardless of the particular method employed, the resulting liquidcrystalline polymer typically may have a high number average molecularweight (M_(n)) of about 2,000 grams per mole or more, in someembodiments from about 4,000 grams per mole or more, and in someembodiments, from about 5,000 to about 30,000 grams per mole. Of course,it is also possible to form polymers having a lower molecular weight,such as less than about 2,000 grams per mole, using the method of thepresent invention. The intrinsic viscosity of the polymer, which isgenerally proportional to molecular weight, may also be relatively high.For example, the intrinsic viscosity may be about 4 deciliters per gram(“dL/g”) or more, in some embodiments about 5 dL/g or more, in someembodiments from about 6 to about 20 dL/g, and in some embodiments fromabout 7 to about 15 dL/g. Intrinsic viscosity may be determined inaccordance with ISO-1628-5 using a 50/50 (v/v) mixture ofpentafluorophenol and hexafluoroisopropanol.

As indicated above, the thermoplastic composition of the presentinvention also contains at least one hydroxy-functional compound as aflow modifier. Such compounds contain one or more hydroxyl functionalgroups that can react with the polymer chain to shorten its length andthus reduce melt viscosity. The hydroxy-functional compounds typicallyconstitute from about 0.05 wt. % to about 4 wt. %, in some embodimentsfrom about 0.1 wt. % to about 2 wt. %, and in some embodiments, fromabout 0.2 wt. % to about 1 wt. % of the thermoplastic composition. Oneexample of a suitable hydroxy-functional compound is an aromatic did,such as hydroquinone, resorcinol, 4,4′-biphenol, etc., as well ascombinations thereof. When employed, such aromatic diols may constitutefrom about 0.01 wt. % to about 1 wt. %, and in some embodiments, fromabout 0.05 wt. % to about 0.4 wt. % of the thermoplastic composition.Water is also a suitable hydroxy-functional compound, and can be usedalone or in combination with other hydroxy-functional compounds. Ifdesired, water can be added in a form that under process conditionsgenerates water. For example, the water can be added as a hydrate thatunder the process conditions (e.g., high temperature) effectively“loses” water. Such hydrates include alumina trihydrate, copper sulfatepentahydrate, barium chloride dihydrate, calcium sulfate dehydrate,etc., as well as combinations thereof. When employed, the hydrates mayconstitute from about 0.02 wt. % to about 2 wt. %, and in someembodiments, from about 0.05 wt. % to about 1 wt. % of the thermoplasticcomposition.

In one particular embodiment, a mixture of an aromatic diol and hydrateare employed as hydroxy-functional compounds in the composition. Thepresent inventors have discovered that this specific combination ofcompounds can reduce melt viscosity and improve flow, but without havingan adverse impact on mechanical properties. Typically, the weight ratioof hydrates to aromatic diols in the mixture is from about 0.5 to about8, in some embodiments from about 0.8 to about 5, and in someembodiments, from about 1 to about 5.

Aromatic dicarboxylic acids are also employed in the thermoplasticcomposition. Without intending to be limited by theory, it is believedthat such acids can combine smaller chains of the polymer together afterthey have been cut by hydroxy-functional compounds. This helps maintainthe mechanical properties of the composition even after its meltviscosity has been reduced. Suitable aromatic dicarboxylic acids forthis purpose may include, for instance, terephthalic acid,2,6-naphthalenedicarboxylic acid, isophthalic acid, 4,4′-bibenzoic acid,2-methylterephthalic acid, etc., as well as combinations thereof. Thedicarboxylic acids typically constitute from about 0.001 wt. % to about0.5 wt. %, and in some embodiments, from about 0.005 wt. % to about 0.1wt. % of the thermoplastic composition.

In addition to the components identified above, various other additivesmay also be incorporated in the thermoplastic composition if desired.For example, fibers may be employed in the thermoplastic composition toimprove the mechanical properties. Such fibers generally have a highdegree of tensile strength relative to their mass. For example, theultimate tensile strength of the fibers (determined in accordance withASTM D2101) is typically from about 1,000 to about 15,000 Megapascals(“MPa”), in some embodiments from about 2,000 MPa to about 10,000 MPa,and in some embodiments, from about 3,000 MPa to about 6,000 MPa. Tohelp maintain an insulative property, which is often desirable for usein electronic components, the high strength fibers may be formed frommaterials that are also generally insulative in nature, such as glass,ceramics (e.g., alumina or silica), aramids (e.g., Kevlar® marketed byE. I. DuPont de Nemours, Wilmington, Del.), polyolefins, polyesters,etc., as well as mixtures thereof. Glass fibers are particularlysuitable, such as E-glass, A-glass, C-glass, D-glass, AR-glass, R-glass,S1-glass, S2-glass, etc., and mixtures thereof.

The volume average length of the fibers may be from about 1 to about 400micrometers, in some embodiments from about 50 to about 400 micrometers,in some embodiments from about 80 to about 250 micrometers, in someembodiments from about 100 to about 200 micrometers, and in someembodiments, from about 110 to about 180 micrometers. The fibers mayalso have a narrow length distribution. That is, at least about 70% byvolume of the fibers, in some embodiments at least about 80% by volumeof the fibers, and in some embodiments, at least about 90% by volume ofthe fibers have a length within the range of from about 50 to about 400micrometers, in some embodiments from about 80 to about 250 micrometers,in some embodiments from about 100 to about 200 micrometers, and in someembodiments, from about 110 to about 180 micrometers. Such a weightaverage length and narrow length distribution can further help achieve adesirable combination of strength and flowability, which enables it tobe uniquely suited for molded parts with a small dimensional tolerance.

In addition to possessing the length characteristics noted above, thefibers may also have a relatively high aspect ratio (average lengthdivided by nominal diameter) to help improve the mechanical propertiesof the resulting thermoplastic composition. For example, the fibers mayhave an aspect ratio of from about 2 to about 50, in some embodimentsfrom about 4 to about 40, and in some embodiments, from about 5 to about20 are particularly beneficial. The fibers may, for example, have anominal diameter of about 10 to about 35 micrometers, and in someembodiments, from about 15 to about 30 micrometers.

The relative amount of the fibers in the thermoplastic composition isalso selectively controlled to help achieve the desired mechanicalproperties without adversely impacting other properties of thecomposition, such as its flowability. For example, the fibers typicallyconstitute from about 2 wt % to about 40 wt. %, in some embodiments fromabout 5 wt. % to about 35 wt. %, and in some embodiments, from about 6wt. % to about 30 wt. % of the thermoplastic composition. Although thefibers may be employed within the ranges noted above, one particularlybeneficial and surprising aspect of the present invention is that smallfiber contents may be employed while still achieving the desiredmechanical properties. Without intending to be limited by theory, it isbelieved that the narrow length distribution of the fibers can helpachieve excellent mechanical properties, thus allowing for the use of asmaller amount of fibers. For example, the fibers can be employed insmall amounts such as from about 2 wt. % to about 20 wt. %, in someembodiments, from about 5 wt. % to about 16 wt. %, and in someembodiments, from about 6 wt. % to about 12 wt. %.

Still other additives that can be included in the composition mayinclude, for instance, antimicrobials, fillers, pigments, antioxidants,stabilizers, surfactants, waxes, solid solvents, and other materialsadded to enhance properties and processability. For example, mineralfillers may be employed in the thermoplastic composition to help achievethe desired mechanical properties and/or appearance. When employed, suchmineral fillers typically constitute from about 1 wt. % to about 40 wt.%, in some embodiments from about 2 wt. % to about 35 wt. %, and in someembodiments, from about 5 wt. % to about 30 wt. % of the thermoplasticcomposition. Clay minerals may be particularly suitable for use in thepresent invention. Examples of such clay minerals include, for instance,talc (Mg₃Si₄O₁₀(OH)₂), halloysite (Al₂Si₂O₅(OH)₄), kaolinite(Al₂Si₂O₅(OH)₄), illite ((K,H₃O)(Al,Mg,Fe)₂(Si,Al)₄O₁₀[(OH)₂,(H₂O)]),montmorillonite (Na,Ca)_(0.33)(Al,Mg)₂Si₄O₁₀(OH)₂.nH₂O), vermiculite((MgFe,Al)₃(Al,Si)₄O₁₀(OH)₂.4H₂O), palygorskite((Mg,Al)₂Si₄O₁₀(OH).4(H₂O)), pyrophyllite (Al₂Si₄O₁₀(OH)₂), etc., aswell as combinations thereof. In lieu of, or in addition to, clayminerals, still other mineral fillers may also be employed. For example,other suitable silicate fillers may also be employed, such as calciumsilicate, aluminum silicate, mica, diatomaceous earth, wollastonite, andso forth. Mica, for instance, may be particularly suitable. There areseveral chemically distinct mica species with considerable variance ingeologic occurrence, but all have essentially the same crystalstructure. As used herein, the term “mica” is meant to genericallyinclude any of these species, such as muscovite (KAl₂(AlSi₃)O₁₀(OH)₂),biotite (K(Mg,Fe)₃(AlSi₃)O₁₀(OH)₂), phlogopite (KMg₃(AlSi₃)O₁₀(OH)₂),lepidolite (K(Li,Al)₂₋₃(AlSi₃)O₁₀(OH)₂), glauconite(K,Na)(Al,Mg,Fe)₂(Si,Al)₄O₁₀(OH)₂), etc., as well as combinationsthereof.

Lubricants may also be employed in the thermoplastic composition thatare capable of withstanding the processing conditions of the liquidcrystalline polymer without substantial decomposition. Examples of suchlubricants include fatty acids esters, the salts thereof, esters, fattyacid amides, organic phosphate esters, and hydrocarbon waxes of the typecommonly used as lubricants in the processing of engineering plasticmaterials, including mixtures thereof. Suitable fatty acids typicallyhave a backbone carbon chain of from about 12 to about 60 carbon atoms,such as myristic acid, palmitic acid, stearic acid, arachic acid,montanic acid, octadecinic acid, parinric acid, and so forth. Suitableesters include fatty acid esters, fatty alcohol esters, wax esters,glycerol esters, glycol esters and complex esters. Fatty acid amidesinclude fatty primary amides, fatty secondary amides, methylene andethylene bisamides and alkanolamides such as, for example, palmitic acidamide, stearic acid amide, oleic acid amide, N,N′-ethylenebisstearamideand so forth. Also suitable are the metal salts of fatty acids such ascalcium stearate, zinc stearate, magnesium stearate, and so forth;hydrocarbon waxes, including paraffin waxes, polyolefin and oxidizedpolyolefin waxes, and microcrystalline waxes. Particularly suitablelubricants are acids, salts, or amides of stearic acid, such aspentaerythritol tetrastearate, calcium stearate, orN,N′-ethylenebisstearamide. When employed, the lubricant(s) typicallyconstitute from about 0.05 wt. % to about 1.5 wt. %, and in someembodiments, from about 0.1 wt. % to about 0.5 wt. % (by weight) of thethermoplastic composition.

The liquid crystalline polymer, flow modifiers, and other optionaladditives may be melt blended together within a temperature range offrom about 200° C. to about 450° C., in some embodiments, from about220° C. to about 400° C., and in some embodiments, from about 250° C. toabout 350° C. to form the thermoplastic composition. Any of a variety ofmelt blending techniques may generally be employed in the presentinvention. For example, the components (e.g., liquid crystallinepolymer, flow modifiers, etc.) may be supplied separately or incombination to an extruder that includes at least one screw rotatablymounted and received within a barrel (e.g., cylindrical barrel) and maydefine a feed section and a melting section located downstream from thefeed section along the length of the screw.

The extruder may be a single screw or twin screw extruder. Referring toFIG. 3, for example, one embodiment of a single screw extruder 80 isshown that contains a housing or barrel 114 and a screw 120 rotatablydriven on one end by a suitable drive 124 (typically including a motorand gearbox). If desired, a twin-screw extruder may be employed thatcontains two separate screws. The configuration of the screw is notparticularly critical to the present invention and it may contain anynumber and/or orientation of threads and channels as is known in theart. As shown in FIG. 3, for example, the screw 120 contains a threadthat forms a generally helical channel radially extending around a coreof the screw 120. A hopper 40 is located adjacent to the drive 124 forsupplying the liquid crystalline polymer and/or other materials (e.g.,flow modifiers) through an opening in the barrel 114 to the feed section132. Opposite the drive 124 is the output end 144 of the extruder 80,where extruded plastic is output for further processing.

A feed section 132 and melt section 134 are defined along the length ofthe screw 120. The feed section 132 is the input portion of the barrel114 where the liquid crystalline polymer and/or flow modifiers areadded. The melt section 134 is the phase change section in which theliquid crystalline polymer is changed from a solid to a liquid. Whilethere is no precisely defined delineation of these sections when theextruder is manufactured, it is well within the ordinary skill of thosein this art to reliably identify the feed section 132 and the meltsection 134 in which phase change from solid to liquid is occurring.Although not necessarily required, the extruder 80 may also have amixing section 136 that is located adjacent to the output end of thebarrel 114 and downstream from the melting section 134. If desired, oneor more distributive and/or dispersive mixing elements may be employedwithin the mixing and/or melting sections of the extruder. Suitabledistributive mixers for single screw extruders may include, forinstance, Saxon, Dulmage, Cavity Transfer mixers, etc. Likewise,suitable dispersive mixers may include Blister ring, Leroy/Maddock, CRDmixers, etc. As is well known in the art, the mixing may be furtherimproved by using pins in the barrel that create a folding andreorientation of the polymer melt, such as those used in Buss Kneaderextruders, Cavity Transfer mixers, and Vortex Intermeshing Pin mixers.

When employed, fibers can also be added to the hopper 40 or at alocation downstream therefrom. In one particular embodiment, fibers maybe added a location downstream from the point at which the liquidcrystalline polymer is supplied, but yet prior to the melting section.In FIG. 3, for instance, a hopper 42 is shown that is located within azone of the feed section 132 of the extruder 80. The fibers supplied tothe hopper 42 may be initially relatively long, such as having a volumeaverage length of from about 1,000 to about 5,000 micrometers, in someembodiments from about 2,000 to about 4,500 micrometers, and in someembodiments, from about 3,000 to about 4,000 micrometers. Nevertheless,by supplying these long fibers at a location where the liquidcrystalline polymer is still in a solid state, the polymer can act as anabrasive agent for reducing the size of the fibers to a volume averagelength and length distribution as indicated above.

If desired, the ratio of the length (“L”) to diameter (“D”) of the screwmay be selected to achieve an optimum balance between throughput andfiber length reduction. The LID value may, for instance, range fromabout 15 to about 50, in some embodiments from about 20 to about 45, andin some embodiments from about 25 to about 40. The length of the screwmay, for instance, range from about 0.1 to about 5 meters, in someembodiments from about 0.4 to about 4 meters, and in some embodiments,from about 0.5 to about 2 meters. The diameter of the screw may likewisebe from about 5 to about 150 millimeters, in some embodiments from about10 to about 120 millimeters, and in some embodiments, from about 20 toabout 80 millimeters. The L/D ratio of the screw after the point atwhich the fibers are supplied may also be controlled within a certainrange. For example, the screw has a blending length (“L_(B)”) that isdefined from the point at which the fibers are supplied to the extruderto the end of the screw, the blending length being less than the totallength of the screw. As noted above, it may be desirable to add thefibers before the liquid crystalline polymer is melted, which means thatthe L_(B)/D ratio would be relatively high. However, too high of aL_(B)/D ratio could result in degradation of the polymer. Therefore, theL_(B)/D ratio of the screw after the point at which the fibers aresupplied is typically from about 4 to about 20, in some embodiments fromabout 5 to about 15, and in some embodiments, from about 6 to about 10.

In addition to the length and diameter, other aspects of the extrudermay also be selected to help achieve the desired fiber length. Forexample, the speed of the screw may be selected to achieve the desiredresidence time, shear rate, melt processing temperature, etc. Generally,an increase in frictional energy results from the shear exerted by theturning screw on the materials within the extruder and results in thefracturing of the fibers, if employed. The degree of fracturing maydepend, at least in part, on the screw speed. For example, the screwspeed may range from about 50 to about 800 revolutions per minute(“rpm”), in some embodiments from about 70 to about 150 rpm, and in someembodiments, from about 80 to about 120 rpm. The apparent shear rateduring melt blending may also range from about 100 seconds⁻¹ to about10,000 seconds⁻¹, in some embodiments from about 500 seconds⁻¹ to about5000 seconds⁻¹, and in some embodiments, from about 800 seconds⁻¹ toabout 1200 seconds⁻¹. The apparent shear rate is equal to 4Q/πR³, whereQ is the volumetric flow rate (“m³/s”) of the polymer melt and R is theradius (“m”) of the capillary (e.g., extruder die) through which themelted polymer flows.

In the embodiments described above, the length of the fibers is reducedwithin the extruder. It should be understood, however, that this is byno means a requirement of the present invention. For example, the fibersmay simply be supplied to the extruder at the desired length. In suchembodiments, the fibers may, for example, be supplied at the mixingand/or melting sections of the extruder, or even at the feed section inconjunction with the liquid crystalline polymer. In yet otherembodiments, fibers may not be employed at all.

Once formed, the thermoplastic composition may be molded into any of avariety of different shaped parts using techniques as is known in theart. For example, the shaped parts may be molded using a one-componentinjection molding process in which dried and preheated plastic granulesare injected into the mold. Regardless of the molding techniqueemployed, it has been discovered that the thermoplastic composition ofthe present invention, which possesses the unique combination of highflowability and good mechanical properties, is particularly well suitedfor parts having a small dimensional tolerance. Such parts, for example,generally contain at least one micro-sized dimension (e.g., thickness,width, height, etc.), such as from about 500 micrometers or less, insome embodiments from about 100 to about 450 micrometers, and in someembodiments, from about 200 to about 400 micrometers.

One such part is a fine pitch electrical connector. More particularly,such electrical connectors are often employed to detachably mount acentral processing unit (“CPU”) to a printed circuit board. Theconnector may contain insertion passageways that are configured toreceive contact pins. These passageways are defined by opposing walls,which may be formed from a thermoplastic resin. To help accomplish thedesired electrical performance, the pitch of these pins is generallysmall to accommodate a large number of contact pins required within agiven space. This, in turn, requires that the pitch of the pin insertionpassageways and the width of opposing walls that partition thosepassageways are also small. For example, the walls may have a width offrom about 500 micrometers or less, in some embodiments from about 100to about 450 micrometers, and in some embodiments, from about 200 toabout 400 micrometers. In the past, it has often been difficult toadequately fill a mold of such a thin width with a thermoplastic resin.Due to its unique properties, however, the thermoplastic composition ofthe present invention is particularly well suited to form the walls of afine pitch connector.

One particularly suitable fine pitch electrical connector is shown inFIG. 1. An electrical connector 200 is shown that a board-side portionC2 that can be mounted onto the surface of a circuit board P. Theconnector 200 may also include a wiring material-side portion C1structured to connect discrete wires 3 to the circuit board P by beingcoupled to the board-side connector C2. The board-side portion C2 mayinclude a first housing 10 that has a fitting recess 10 a into which thewiring material-side connector C1 is fitted and a configuration that isslim and long in the widthwise direction of the housing 10. The wiringmaterial-side portion C1 may likewise include a second housing 20 thatis slim and long in the widthwise direction of the housing 20. In thesecond housing 20, a plurality of terminal-receiving cavities 22 may beprovided in parallel in the widthwise direction so as to create atwo-tier array including upper and lower terminal-receiving cavities 22.A terminal 5, which is mounted to the distal end of a discrete wire 3,may be received within each of the terminal-receiving cavities 22. Ifdesired, locking portions 28 (engaging portions) may also be provided onthe housing 20 that correspond to a connection member (not shown) on theboard-side connector C2.

As discussed above, the interior walls of the first housing 10 and/orsecond housing 20 may have a relatively small width dimension, and canbe formed from the thermoplastic composition of the present invention.The walls are, for example, shown in more detail in FIG. 2. Asillustrated, insertion passageways or spaces 225 are defined betweenopposing walls 224 that can accommodate contact pins. The walls 224 havea width “w” that is within the ranges noted above. When the walls 224are formed from a thermoplastic composition containing fibers (e.g.,element 400), such fibers may have a volume average length and narrowlength distribution within a certain range to best match the width ofthe walls. For example, the ratio of the width of at least one of thewalls to the volume average length of the fibers is from about 0.8 toabout 3.2, in some embodiments from about 1.0 to about 3.0, and in someembodiments, from about 1.2 to about 2.9.

In addition to or in lieu of the walls, it should also be understoodthat any other portion of the housing may also be formed from thethermoplastic composition of the present invention. For example, theconnector may also include a shield that encloses the housing. Some orall of the shield may be formed from the thermoplastic composition ofthe present invention. For example, the housing and the shield can eachbe a one-piece structure unitarily molded from the thermoplasticcomposition. Likewise, the shield can be a two-piece structure thatincludes a first shell and a second shell, each of which may be formedfrom the thermoplastic composition of the present invention.

Of course, the thermoplastic composition may also be used in a widevariety of other components having a small dimensional tolerance. Forexample, the thermoplastic composition may be molded into a planarsubstrate for use in an electronic component. The substrate may be thin,such as having a thickness of about 500 micrometers or less, in someembodiments from about 100 to about 450 micrometers, and in someembodiments, from about 200 to about 400 micrometers. Examples ofelectronic components that may employ such a substrate include, forinstance, cellular telephones, laptop computers, small portablecomputers (e.g., ultraportable computers, netbook computers, and tabletcomputers), wrist-watch devices, pendant devices, headphone and earpiecedevices, media players with wireless communications capabilities,handheld computers (also sometimes called personal digital assistants),remote controllers, global positioning system (GPS) devices, handheldgaming devices, battery covers, speakers, integrated circuits (e.g., SIMcards), etc.

In one embodiment, for example, the planar substrate may be applied withone or more conductive elements using a variety of known techniques(e.g., laser direct structuring, electroplating, etc.). The conductiveelements may serve a variety of different purposes. In one embodiment,for example, the conductive elements form an integrated circuit, such asthose used in SIM cards. In another embodiment, the conductive elementsform antennas of a variety of different types, such as antennae withresonating elements that are formed from patch antenna structures,inverted-F antenna structures, closed and open slot antenna structures,loop antenna structures, monopoles, dipoles, planar inverted-F antennastructures, hybrids of these designs, etc. The resulting antennastructures may be incorporated into the housing of a relatively compactportable electronic component, such as described above, in which theavailable interior space is relatively small.

One particularly suitable electronic component that includes an antennastructure is shown in FIGS. 4-5 is a handheld device 410 with cellulartelephone capabilities. As shown in FIG. 4, the device 410 may have ahousing 412 formed from plastic, metal, other suitable dielectricmaterials, other suitable conductive materials, or combinations of suchmaterials. A display 414 may be provided on a front surface of thedevice 410, such as a touch screen display. The device 410 may also havea speaker port 440 and other input-output ports. One or more buttons 438and other user input devices may be used to gather user input. As shownin FIG. 5, an antenna structure 426 is also provided on a rear surface442 of device 410, although it should be understood that the antennastructure can generally be positioned at any desired location of thedevice. As indicated above, the antenna structure 426 may contain aplanar substrate that is formed from the thermoplastic composition ofthe present invention. The antenna structure may be electricallyconnected to other components within the electronic device using any ofa variety of known techniques. For example, the housing 412 or a part ofhousing 412 may serve as a conductive ground plane for the antennastructure 426.

A planar substrate that is formed form the thermoplastic composition ofthe present invention may also be employed in other applications. Forexample, in one embodiment, the planar substrate may be used to form abase of a compact camera module (“CCM”), which is commonly employed inwireless communication devices (e.g., cellular phone). Referring toFIGS. 6-7, for example, one particular embodiment of a compact cameramodule 500 is shown in more detail. As shown, the compact camera module500 contains a lens assembly 504 that overlies a base 506. The base 506,in turn, overlies an optional main board 508. Due to their relativelythin nature, the base 506 and/or main board 508 are particularly suitedto be formed from the thermoplastic composition of the present inventionas described above. The lens assembly 504 may have any of a variety ofconfigurations as is known in the art, and may include fixed focus-typelenses and/or auto focus-type lenses. In one embodiment, for example,the lens assembly 504 is in the form of a hollow barrel that houseslenses 604, which are in communication with an image sensor 602positioned on the main board 508 and controlled by a circuit 601. Thebarrel may have any of a variety of shapes, such as rectangular,cylindrical, etc. In certain embodiments, the barrel may also be formedfrom the thermoplastic composition of the present invention and have awall thickness within the ranges noted above. It should be understoodthat other parts of the cameral module may also be formed from thethermoplastic composition of the present invention. For example, asshown, a polymer film 510 (e.g., polyester film) and/or thermalinsulating cap 502 may cover the lens assembly 504. In some embodiments,the film 510 and/or cap 502 may also be formed from the thermoplasticcomposition of the present invention.

Printer parts may also contain the thermoplastic composition of thepresent invention. Examples of such parts may include, for instance,printer cartridges, separation claws, heater holders, etc. For example,the composition may be used to form an ink jet printer or a component ofan inkjet printer. In one particular embodiment, for instance, the inkcartridge may contain a rigid outer housing having a pair of spacedcover plates affixed to a peripheral wall section. In one embodiment,the cover plates and/or the wall section may be formed from thecomposition of the present invention.

The present invention may be better understood with reference to thefollowing examples.

Test Methods

Melt Viscosity: The melt viscosity (Pa-s) may be determined inaccordance with ISO Test No. 11443 at a shear rate of 1000 s⁻¹ andtemperature 15° C. above the melting temperature (e.g., 350° C.) using aDynisco LCR7001 capillary rheometer. The rheometer orifice (die) had adiameter of 1 mm, length of 20 mm, L/D ratio of 20.1, and an entranceangle of 180°. The diameter of the barrel was 9.55 mm+0.005 mm and thelength of the rod was 233.4 mm.

Melting Temperature:

The melting temperature (“Tm”) was determined by differential scanningcalorimetry (“DSC”) as is known in the art. The melting temperature isthe differential scanning calorimetry (DSC) peak melt temperature asdetermined by ISO Test No. 11357. Under the DSC procedure, samples wereheated and cooled at 20° C. per minute as stated in ISO Standard 10350using DSC measurements conducted on a TA Q2000 Instrument.

Deflection Temperature Under Load (“DTUL”):

The deflection under load temperature was determined in accordance withISO Test No. 75-2 (technically equivalent to ASTM D648-07). Moreparticularly, a test strip sample having a length of 80 mm, thickness of10 mm, and width of 4 mm was subjected to an edgewise three-pointbending test in which the specified load (maximum outer fibers stress)was 1.8 Megapascals. The specimen was lowered into a silicone oil bathwhere the temperature is raised at 2° C. per minute until it deflects0.25 mm (0.32 mm for ISO Test No. 75-2).

Tensile Modulus, Tensile Stress, and Tensile Elongation:

Tensile properties are tested according to ISO Test No. 527 (technicallyequivalent to ASTM D638). Modulus and strength measurements are made onthe same test strip sample having a length of 80 mm, thickness of 10 mm,and width of 4 mm. The testing temperature is 23° C., and the testingspeeds are 1 or 5 mm/min.

Flexural Modulus, Flexural Stress, and Flexural Strain:

Flexural properties are tested according to ISO Test No. 178(technically equivalent to ASTM D790), This test is performed on a 64 mmsupport span. Tests are run on the center portions of uncut ISO 3167multi-purpose bars. The testing temperature is 23° C. and the testingspeed is 2 mm/min.

Notched Charpy Impact Strength:

Notched Charpy properties are tested according to ISO Test No. ISO179-1) (technically equivalent to ASTM D256, Method B). This test is runusing a Type A notch (0.25 mm base radius) and Type 1 specimen size(length of 80 mm, width of 10 mm, and thickness of 4 mm). Specimens arecut from the center of a multi-purpose bar using a single tooth millingmachine. The testing temperature is 23° C.

Fiber Length:

The volume average fiber length is determined by initially placingseveral pellet samples (e.g., 7 or 8) in a muffle furnace at 420° C.overnight. The resulting ash is immersed in an aqueous solutioncontaining a glycerol surfactant to disperse the glass fibers. Theaqueous solution is then placed on a glass slide and images arecollected via image analysis system. Glass fibers are selectively chosenfrom the images by ImagePro™ software, and the software automaticallymeasures the length of the selected glass fiber based on calibratedlength. Measurement continues until at least 500 glass fibers arecounted. Then, the volume average fiber length and distribution arecalculated.

Weldline Strength:

The weldline strength is determined by first forming an injection moldedline grid array (“LGA”) connector (size of 49 mm×39 mm×1 mm) from athermoplastic composition sample as is well known in the art. Onceformed, the LGA connector is placed on a sample holder. The center ofthe connector is then subjected to a tensile force by a rod moving at aspeed of 5.08 millimeters per minute. The peak stress is recorded as anestimate of the weldline strength.

EXAMPLE

Three (3) samples of a thermoplastic composition are formed from 67.375wt. % of a liquid crystalline polymer, 10 wt. % glass fibers, 22 wt. %talc, 0.3 wt. % Glycolube™ P, 0.2 wt. % alumina trihydrate, 0.1 wt. %4-biphenol, and 0.025 wt. % 2,6-naphthalene dicarboxylic acid (“NDA”).The liquid crystalline polymer is formed from 4-hydroxybenzoic acid(“HBA”), 2,6-hydroxynaphthoic acid (“HNA”), terephthalic acid (“TA”),4,4′-biphenol (“BP”), and acetaminophen (“APAP”), such as described inU.S. Pat. No. 5,508,374 to Lee, et al. The HNA was employed in an amountof 5 mol. %. The glass fibers are obtained from Owens Corning and had aninitial length of 4 millimeters.

To form the thermoplastic composition, pellets of the liquid crystallinepolymer are dried at 150° C. overnight. Thereafter, the polymer andGlycolube™ P are supplied to the feed throat of a ZSK-25 WLEco-rotating, fully intermeshing twin screw extruder in which the lengthof the screw is 750 millimeters, the diameter of the screw is 25millimeters, and the L/D ratio is 30. The extruder has Temperature Zones1-9, which may be set to the following temperatures: 330° C., 330° C.,310° C., 310° C., 310° C., 310° C., 320° C., 320° C., and 320° C.,respectively. For Samples 1-2, the screw design is selected so thatmelting occurs after Zone 4. For Sample 3, the screw design is selectedso that melting begins prior to Zone 4. The polymer is supplied to thefeed throat by means of a volumetric feeder. The glass fibers and talcare fed to Zones 4 and/or 6 as indicated in the table below. Once meltblended, the samples are extruded through a single-hole strand die,cooled through a water bath, and pelletized.

The samples are then tested for fiber length in the manner indicatedabove. The results are set forth in Table 1 below.

TABLE 1 Sample 1 Sample 2 Sample 3 Feeding Glass fibers Glass fibersGlass fibers sequence at Zone #4; at Zone #6; at Zone #4; Talc Talc Talcat Zone #6 at Zone #4 at Zone #6 L/D after GF 7.75 3.90 6.75 feeding L/Dbefore GF 0 3.85 4.80 feeding Glass fiber length Vol. Average 140 390320 (μm) Vol. Standard 0.07 0.27 0.20 Deviation Max 0.41 1.56 0.98 Count1187 1462 794 Coefficient of 51 96 89 Variance (%)

As indicated in Table 1, when the glass fibers are fed at Zone #4(Sample 1, L/D after glass fiber feeding=7.75), the fiber length becomeseffectively shorter and its distribution is narrower. When fed at Zone#6 (Sample 2, LID after glass fiber feeding=3.90) or at Zone #4 butafter melting of the polymer (Sample 3, L/D after glass fiberfeeding=4.80), however, no significant change in length is observed.

Parts are injection molded from Samples 1-3 and tested for their thermaland mechanical properties. The results are set forth below in Table 2.

TABLE 2 Sample 1 Sample 2 Sample 3 Melt Viscosity at 18.4 17.6 19.3 1000s⁻¹ and 350° C. (Pa-s) Melt Viscosity at 23 24.9 24.2 400 s⁻¹ and 350°C. (Pa-s) DTUL @ 1.8 Mpa (° C.) 238 254 247 Ten. Brk stress (MPa) 118125 122 Ten. Modulus (MPa) 10,711 11,811 11,318 Ten. Brk strain (%) 2.62.1 2.4 Flex Brk stress (MPa) 139 166 16.1 Flex modulus (MPa) 10,94111,496 12,102 Flex Brk strain (%) 3.1 2.5 2.6 Charpy Notched (KJ/m²) 7.518.0 9.7

Example 2

Six (6) samples of a thermoplastic composition are formed from 67.375wt. % of a liquid crystalline polymer, 30 wt. % glass fibers, 20 wt. %talc, 0.3 wt. % Glycolube™ P, 0.2 wt. % alumina trihydrate, 0.1 wt. %4-biphenol, and 0.025 wt. % 2,6-naphthalene dicarboxylic acid (“NDA”).The liquid crystalline polymer and glass fibers are the same as employedin Example 1. To form the thermoplastic composition, pellets of theliquid crystalline polymer are dried at 150° C. overnight. Thereafter,the polymer and Glycolube™ P are supplied to the feed throat of a ZSK-25WLE co-rotating, fully intermeshing twin screw extruder in which thelength of the screw is 750 millimeters, the diameter of the screw is 25millimeters, and the L/D ratio is 30. The extruder has Temperature Zones1-9, which may be set to the following temperatures: 330° C., 330° C.,310° C., 310° C., 310° C., 310° C., 320° C., 320° C., and 320° C.,respectively. The screw design is selected so that melting begins atZone 4. The polymer is supplied to the feed throat by means of avolumetric feeder. The glass fibers and talc are fed to Zones 4 and/or 6as indicated in the table below, Once melt blended, the samples areextruded through a single-hole strand die, cooled through a water bath,and pelletized.

The samples are then tested for fiber length in the manner indicatedabove. The results are set forth in the table below in Table 3.

TABLE 3 Sample Sample Sample Sample Sample Sample 4 5 6 7 8 9 FeedingGlass Glass Glass Glass Glass Glass sequence fibers at fibers at fibersat fibers at fibers at fibers at Zone Zone Zone Zone Zone Zone #4; #4;#4; #4; #6; #6; Talc at Talc at Talc at Talc at Talc at Talc at Zone #6Zone #6 Zone #6 Zone #6 Zone #4 Zone #4 L/D after 7.75 7.75 7.75 7.753.90 3.90 GF feeding L/D before 0 0 0 0 3.85 3.85 GF feeding Glass fiberlength Vol. Average 90 100 100 110 370 350 (μm) Vol. Standard 0.05 0.060.05 0.06 0.17 0.18 Deviation Max 0.37 0.45 0.44 0.39 1.07 1.19 Count3038 2584 1568 2295 1046 1266 Coefficient 53 53 51 57 54 58 of Variance(%)

As indicated in Table 3, when the glass fibers are fed at Zone #4(Samples 4-7, L/D after glass fiber feeding=7.75), the fiber lengthbecomes effectively shorter and its distribution is narrower. When fedat Zone #6 (Samples 8-9, L/D after glass fiber feeding=3.90), however,no significant change in length is observed.

Parts are injection molded from Samples 4-9 and tested for their thermaland mechanical properties. The results are set forth below in Table 4.

TABLE 4 Sample Sample Sample Sample Sample Sample 4 5 6 7 8 9 MeltViscosity 38.4 31.1 34.9 29.2 23.6 21.3 at 1000 s⁻¹ and 350° C. (Pa-s)Melt Viscosity 54.2 42.6 48.6 39.7 36.6 32 at 400 s⁻¹ and 350° C. (Pa-s)DTUL @ 1.8 233 235 230 238 253 251 Mpa (° C.) Ten. Brk stress 92 94 8994 108 100 (MPa) Ten. Modulus 11,725 12,093 11,060 11,404 16,270 14,736(MPa) Ten. Brk strain 2.7 2.5 2.4 2.6 0.9 0.9 (%) Flex Brk stress 132132 124 128 158 142 (MPa) Flex modulus 12,966 13,136 12,246 12,45016,662 15,042 (MPa) Flex Brk strain 2.3 2.2 2.3 2.3 1.24 1.3 (%) CharpyNotched 3.7 4.3 3.2 3.8 6.3 5.0 (KJ/m²)

Example 3

Six (6) samples of a thermoplastic composition are formed from 49.375wt. % of a liquid crystalline polymer, 0.3 wt. % Glycolube™ P, 0.2 wt. %alumina trihydrate, 0.1 wt. % 4-biphenol, 0.025 wt. % 2,6-naphthalenedicarboxylic acid (“NDA”), and varying percentages of glass fibers andmineral filler (talc or mica). The liquid crystalline polymer of Samples10-15 is the same as employed in Example 1. The liquid crystallinepolymer of Samples 16-17 is formed from 4-hydroxybenzoic acid (“HBA”),NDA, terephthalic acid (“TA”), isophthalic acid (“IA”), hydroquinone(“HQ”), and acetaminophen (“APAP”). The NDA was employed in an amount of12.5 mol. %.

To form the thermoplastic composition, pellets of the liquid crystallinepolymer are dried at 150° C. overnight. Thereafter, the polymer andGlycolube™ P are supplied to the feed throat of a ZSK-25 WLEco-rotating, fully intermeshing twin screw extruder in which the lengthof the screw is 750 millimeters, the diameter of the screw is 25millimeters, and the LID ratio is 30. The extruder has Temperature Zones1-9, which may be set to the following temperatures: 330° C., 330° C.,310° C., 310° C., 310° C., 310° C., 320° C., 320° C., and 320° C.,respectively. The screw design is selected so that melting begins atZone 4. The polymer is supplied to the feed throat by means of avolumetric feeder. The glass fibers and talc are fed to Zone 4. Oncemelt blended, the samples are extruded through a single-hole strand die,cooled through a water bath, and pelletized.

The samples are then tested for fiber length in the manner indicatedabove. The results are set forth in the table below in Table 5.

TABLE 5 Sample Sample Sample Sample Sample Sample Sample Sample 10 11 1213 14 15 16 17 Mineral Filler Talc Talc Talc Talc Talc Mica Mica TalcWt. % of 22.0 10 16.0 27 13 22 22.0 22.0 Mineral Filler Wt. % of 10.0 2016.0 13 27 10 10.0 10.0 Glass Fibers Glass fiber length Vol. Average0.12 0.11 0.12 0.10 0.10 0.10 0.10 0.09 (μm) Vol. Standard 0.08 0.070.08 0.05 0.07 0.06 0.06 0.05 Deviation Max 0.5 0.46 0.51 0.35 0.47 0.360.32 0.28 Count 1198 1893 1845 914 1390 1235 787 847 Coefficient 66 6768 56 66 61 59 58 of Variance (%)

As indicated, no significant change in fiber length and distribution isobserved by changing filler ratio and filler content.

Parts are injection molded from Samples 10-17 and tested for theirthermal and mechanical properties. The results are set forth below.

Sample Sample Sample Sample Sample Sample Sample Sample 10 11 12 13 1415 16 17 Melt Viscosity 17 18 19 19 27 24 23 17 at 1000 s⁻¹ and 350° C.(Pa-s) Melt Viscosity 24 22 25 25 37 32 31 22 at 400 s⁻¹ and 350° C.(Pa-s) DTUL @ 1.8 232 235 234 241 238 243 258 238 Mpa (° C.) Ten. Brkstress 116 125 116 108 114 121 143 131 (MPa) Ten. Modulus 10,423 11,83611,417 11,295 12,728 13,646 15,903 12,269 (MPa) Ten. Brk strain 2.742.67 2.85 2.49 2.48 2.09 1.87 2.18 Flex Brk stress 138 153 145 137 155162 184 159 (MPa) Flex modulus 11,019 12,065 12,047 11,835 13,364 14,77316,372 12,196 (MPa) Flex Brk strain 2.93 2.9 2.7 2.6 2.51 2.41 2.25 2.91(%) Charpy Notched 15.4 24.4 14.3 5.1 12.6 5.0 4.6 12.8 (KJ/m²)

Example 4

Two (2) samples of a thermoplastic composition are formed from 64.375wt. % of a liquid crystalline polymer, 18 wt. % glass fibers, 18 wt. %talc, 0.3 wt. % Glycolube™ P, 0.2 wt. % alumina trihydrate, 0.1 wt. %4-biphenol, and 0.025 wt. % 2,6-napthalene dicarboxylic acid (“NDA”).The liquid crystalline polymer and the glass fibers are the same asemployed in Example 1. To form the thermoplastic composition, pellets ofthe liquid crystalline polymer are dried at 150° C. overnight.Thereafter, the polymer and Glycolube™ P are supplied to the feed throatof a ZSK-25 WLE co-rotating, fully intermeshing twin screw extruder inwhich the length of the screw is 750 millimeters, the diameter of thescrew is 32 millimeters, and the L/D ratio is 30. The extruder hasTemperature Zones 1-9, which may be set to the following temperatures:330° C., 330° C., 310° C., 310° C., 310° C., 310° C., 320° C., 320° C.,and 320° C., respectively. The screw design is selected so that meltingoccurs after Zone 4. The polymer is supplied to the feed throat by meansof a volumetric feeder. The glass fibers and talc are fed to Zones 4 and6, respectively. Once melt blended, the sample is extruded through asingle-hole strand die, cooled through a water bath, and pelletized.

The sample is then tested for fiber length in the manner indicatedabove. The results are set forth in Table 6 below.

TABLE 6 Sample 18 L/D after GF feeding 7.75 L/D before GF feeding 0 Vol.Average Length of Fibers (μm) 120 Vol. Standard Deviation of Fibers 0.08Max 0.51 Count 1845 Coefficient of Variance (%) 68

A part is injection molded from Sample 18 and tested for its thermal andmechanical properties. The results are set forth below in Table 7.

TABLE 7 Sample 18 Melt Viscosity at 16.5 1000 s⁻¹ and 350° C. (Pa-s)DTUL @ 1.8 MPa (° C.) 230 Ten. Brk stress (MPa) 102 Ten. Modulus (MPa)10,620 Ten. Brk strain (%) 2.60 Flex Brk stress (MPa) 132 Flex modulus(MPa) 11,401 Flex Brk strain (%) 2.5 Charpy Notched (KJ/m²) 4.0 WeldLine Strength (kPa) 58

Example 5

A thermoplastic composition are formed from 69.375 wt. % of a liquidcrystalline polymer, 30 wt. % glass fibers, 0.3 wt. % lubricant, 0.2 wt.% alumina trihydrate, 0.1 wt. % 4-biphenol, and 0.025 wt. %2,6-napthalene dicarboxylic acid (“NDA”). The liquid crystalline polymeris the same as employed in Example 1. To form the thermoplasticcomposition, pellets of the liquid crystalline polymer are dried at 150°C. overnight and then coated with 0.3 wt. % of a Licowax™ lubricant.Thereafter, the additives were applied to the mixture, which wasagitated to ensure uniform mixing, and supplied to the feed throat of aZSK-25 WLE co-rotating, fully intermeshing twin screw extruder in whichthe diameter of the screw is 25 millimeters. The extruder hasTemperature Zones 1-8, which may be set to the following temperatures:320° C., 320° C., 330° C., 310° C., 310° C., 310° C., 320° C., and 330°C., respectively. The polymer is supplied to the feed throat by means ofa volumetric feeder. The glass fibers are fed to Zone 4. Once meltblended, the sample is extruded through a single-hole strand die, cooledthrough a water bath, and pelletized.

An LGA connector is injection molded from and tested for its thermal andmechanical properties. The results are set forth below in Table 8.

TABLE 8 Sample 19 Melt Viscosity at 16.6 1000 s⁻¹ and 350° C. (Pa-s)DTUL @ 1.8 Mpa (° C.) 257.4 Ten. Brk stress (MPa) 153 Ten. Modulus (MPa)16,775 Ten. Brk strain (%) 1.6 Flex Brk stress (MPa) 214.4 Flex modulus(MPa) 15,713 Flex Brk strain (%) 2.3

Example 6

A thermoplastic composition are formed from 67.375 wt. % of a liquidcrystalline polymer, 28 wt. % glass fibers, 0.3 wt. % lubricant, 0.2 wt.% alumina trihydrate, 0.1 wt. % 4-biphenol, and 0.025 wt. %2,6-napthalene dicarboxylic acid (“NDA”) in the manner described inExample 5. The liquid crystalline polymer is the same as employed inSamples 16-17 above. An LGA connector is injection molded from andtested for its thermal and mechanical properties. The results are setforth below in Table 9.

TABLE 9 Sample 20 Melt Viscosity at 7.9 1000 s⁻¹ and 350° C. (Pa-s) DTUL@ 1.8 Mpa (° C.) 267.4 Ten. Brk stress (MPa) 109.6 Ten. Modulus (MPa)12,953 Ten. Brk strain (%) 1.1 Flex Brk stress (MPa) 168 Flex modulus(MPa) 12,700 Flex Brk strain (%) 1.7

Example 7

A thermoplastic composition are formed from 68.375 wt. % of a liquidcrystalline polymer, 27 wt. % glass fibers, 0.3 wt. % lubricant, 0.2 wt.% alumina trihydrate, 0.1 wt. % 4-biphenol, and 0.025 wt. %2,6-napthalene dicarboxylic acid (“NDA”) in the manner described inExample 5. The liquid crystalline polymer is formed from HBA, TA, IA,APAP, HQ, and BP. An LGA connector is injection molded from and testedfor its thermal and mechanical properties. The results are set forthbelow in Table 10.

TABLE 10 Sample 21 Melt Viscosity at 12.8 1000 s⁻¹ and 350° C. (Pa-s)DTUL @ 1.8 Mpa (° C.) 246.9 Ten. Brk stress (MPa) 151.5 Ten. Modulus(MPa) 18,413 Ten. Brk strain (%) 1.2 Flex Brk stress (MPa) 203.3 Flexmodulus (MPa) 17,306 Flex Brk strain (%) 2.0

Example 8

A thermoplastic composition are formed from 68.375 wt. % of a liquidcrystalline polymer, 27 wt. % glass fibers, 0.3 wt. % lubricant, 0.2 wt.% alumina trihydrate, 0.1 wt. % 4-biphenol, and 0.025 wt. %2,6-napthalene dicarboxylic acid (“NDA”) in the manner described inExample 5. The liquid crystalline polymer is formed from HBA, TA, HQ,and NDA (20 mol. %). An LGA connector is injection molded from andtested for its thermal and mechanical properties. The results are setforth below in Table 11.

TABLE 11 Sample 22 Melt Viscosity at 20.8 1000 s⁻¹ and 350° C. (Pa-s)DTUL @ 1.8 Mpa (° C.) 280.6 Ten. Brk stress (MPa) 160.1 Ten. Modulus(MPa) 12.636 Ten. Brk strain (%) 2.9 Flex Brk stress (MPa) 196.2 Flexmodulus (MPa) 12,292 Flex Brk strain (%) 3.6

These and other modifications and variations of the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention. Inaddition, it should be understood that aspects of the variousembodiments may be interchanged both in whole or in part. Furthermore,those of ordinary skill in the art will appreciate that the foregoingdescription is by way of example only, and is not intended to limit theinvention so further described in such appended claims.

1. A thermoplastic composition that comprises at least one thermotropicliquid crystalline polymer, wherein the total amount of repeating unitsin the polymer derived from naphthenic hydroxcarboxylic or naphthenicdicarboxylic acids is no more than 15 mol. %, the thermoplasticcomposition further comprising at least one hydroxy-functional compoundand at least one aromatic dicarboxylic acid, wherein the weight ratio ofhydroxy-functional compounds to aromatic dicarboxylic acids in thecomposition is from about 0.1 to about 30, and further wherein thethermoplastic composition has a melt viscosity of from about 0.5 toabout 100 Pa-s, as determined in accordance with ISO Test No. 11443 at ashear rate of 1000 seconds⁻¹ and temperature that is 15° C. above themelting temperature of the composition.
 2. The thermoplastic compositionof claim 1, wherein the weight ratio of hydroxy-functional compounds toaromatic dicarboxylic acids in the composition is from about 1 to about30.
 3. The thermoplastic composition of claim 1, whereinhydroxy-functional compounds constitute from about 0.05 wt. % to about 4wt. % of the thermoplastic composition.
 4. The thermoplastic compositionof claim 1, wherein the hydroxy-functional compound includes an aromaticdiol, hydrate, or a combination thereof.
 5. The thermoplasticcomposition of claim 4, wherein the hydroxy-functional compound includesan aromatic diol selected from the group consisting of hydroquinone,resorcinol, 4,4′-biphenol, and combinations thereof.
 6. Thethermoplastic composition of claim 4, wherein the hydroxy-functionalcompound includes alumina trihydrate.
 7. The thermoplastic compositionof claim 4, wherein the thermoplastic composition contains a mixture ofan aromatic diol and hydrate.
 8. The thermoplastic composition of claim7, wherein the weight ratio of hydrates to aromatic diols in the mixtureis from about 0.5 to about
 8. 9. The thermoplastic composition of claim1, wherein the polymer contains monomer units derived from4-hydroxybenzoic acid, terephthalic acid, hydroquinone, 4,4′-biphenol,acetaminophen, or a combination thereof.
 10. The thermoplasticcomposition of claim 9, wherein the polymer further contains monomerunits derived from 6-hydroxy-2-naphthoic acid in an amount of no morethan 15 mol. %.
 11. The thermoplastic composition of claim 1, whereinthe composition has a melt viscosity of from about 1 to about 80 Pa-s,as determined in accordance with ISO Test No. 11443 at a shear rate of1000 seconds⁻¹ and temperature that is 15° C. above the meltingtemperature of the composition.
 12. The thermoplastic composition ofclaim 1, wherein the composition further comprises fibers having avolume average length of from about 1 to about 400 micrometers.
 13. Thethermoplastic composition of claim 1, wherein thermotropic liquidcrystalline polymers constitute from about 20 wt. % to about 90 wt. % ofthe composition, hydroxy-functional compounds constitute from about 0.05wt. % to about 4 wt. % of the composition, and aromatic dicarboxylicacids constitute from about 0.001 wt. % to about 0.5 wt. % of thecomposition.
 14. The thermoplastic composition of claim 1, wherein thetotal amount of repeating units in the polymer derived from naphthenichydroxcarboxylic or naphthenic dicarboxylic acids is no more than about10 mol. %.
 15. A molded part comprising the thermoplastic composition ofclaim
 1. 16-29. (canceled)